Frequently Asked Questions.
- I have taken off the wallpaper and the surface isn't good enough to paint. What can be done?
- What is Blown Plaster?
- My Ceiling is Sagging and/or Cracks are appearing. Why?
- Can Artex be skimmed over to make walls and/or ceilings smooth again?
- How long do I have to wait after plastering to paint?
I have taken off the wallpaper and the surface isn't good enough to paint. What can be done?
If the Plaster is sound and just needs to be made smooth ready for painting then it can be sealed and Re-skimmed, (PVA and a thin coat of plaster over the existing).
If the plaster is loose (Blown) it will have to be taken back to where the trouble is. Sometimes just the original skim coat has blown so only that has to come off, but sometimes the backing coat has become loose so it has to be taken back to the brickwork. In either case the wall has to then be made dust free by brushing and applying a coat of sealer called PVA prior to re-plastering.
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What is Blown Plaster ?
This is plaster that doesn't have contact with the brick wall anymore and is just managing to hang onto the wall. It can be recognized by knocking with your fingers. You will hear a louder / hollow sound on the blown plaster than in the healthy plaster. Blown plaster should be knocked out and patched up to bring it level with the sound plaster before re-skimming.
It could be just the skim (The smooth thin top coat) that has blown so only that would have to come off before re-skimming.
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My Ceiling is Sagging and/or Cracks are appearing. Why?
Sagging in plaster boarded ceilings is usually due to a leak above and the board has been damaged by the water. The best course of action is to remove the damaged board and replace, PVA the rest of the ceiling and skim the whole ceiling which will allow the patch to be joined properly using a mesh scrim over the join to stop it cracking.
Sagging in Lath and plaster ceiling is where the sand and cement coat has come away from the laths. This has to be removed and repaired by either re-rendering over the laths or plaster boarding and then skimming over the whole ceiling.
Depending on the amount of damage sometimes is is better to replace the whole ceiling.
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Can Artex be skimmed over to make walls and ceilings smooth again?
If the Artex is sound and clean, it can be scraped back, sealed and skimmed over.
If the Artex is loose it will have to come off. New plaster can only be as strong as the background it is applied to.
Sometimes the best course of action with a ceiling is to over board and then skim.
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How long after Plastering do I have to wait to Paint?
When skimming on top of old plaster or plasterboard, you should wait 5-6 days before applying a thinned coat and then 1 or 2 normal coats of paint. If your room has been plastered from the brick, the normal drying time is 10-14 days. In both cases, it will help if you leave windows open. New plaster will take on a light pink colour which tells you it's ready to start painting.
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